build: switch to m4/ac_find_gap.m4
build: remove various generated files
remove CVS leftovers
build: add autogen.sh
build: improve (dist)clean
PackageInfo.g: update URLs
make_dist.sh: do not delete manual.lab
build: switch to automake
build: always set GMP_LIBS and GMP_CPPFLAGS
update .gitignore
Convert manual to GAPDoc format
Convert more functions from K&R to ANSI C
Update include guards
Remove unused src/bit_print.c
Remove trailing whitespace
Add clang-format style
Run clang-format on code